I think that the struggle between George Zimmerman and Trayvon Martin was over the gun that Zimmerman had drawn out while pursuing Martin to capture him. Martin was the one screaming while trying to get the gun away and Zimmerman got his head scratches and nose injury when the two were rolling about over the concrete sidewalk, with Martin eventually getting on top. It was shown that it was physically impossible for Zimmerman to have drawn his gun out of his holster, as he claimed, while he was on the ground and Martin was on top. That means that the gun was already drawn when the “fight” started. Judge Alex had also alluded to this fact in one of his TV interviews about George Zimmerman’s murder trial.